With increasing ecological concerns, there is a great emphasis on conversation of water and minimization of ever-increasing amounts of sewage effluent. The modern conventional domestic flush-toilet wastes water and is a source of excessive volume of sewage effluent. The domestic flush toilet is flushed by moving the external control of a lever mounted on the flush tank to a stop within the lever mechanism and immediately releasing it so as to cause the in-tank arm of the lever to momentarily rise, lift an attached thereto moveable component of the tank flush valve up off its seat to allow a downrush of flush water. The now unseated and unsupported moveable component of the flush valve is held in an open position at the periphery of the down-rushing column of flush water until down rush of water ceases; whereupon, the moveable component of the flush valve falls back upon the valve seat due to gravity. Such a full flush, uncontrolled once started, is always a waste of water and a source of excessive sewage effluent when only urine is flushed; it is often a waste of water and a source of excessive sewage effluent when solid matter is flushed. The instant invention satisfies a need for control of the flushing water so as to stop it at will when contents of the toilet bowl are seen to have been adequately flushed.